Aqi-5 
.L3 



.L5 



■* 



3TE.— This paper is sent to you that you may examine it in advance of tlie 
meeting, and prepare any discussion of it which you may wish to present. 

It is issued to the membership in co».fidence, and with the distinct understand- 
ing that it is not to be given to the press or to the public until after it h;is been 
presented at ihe meeting. 

As there will be no supply of extra copies there, and papers are liable to be read 
by abstract only, preserve this copy for your use, and 

BRING THIS COPY WITH YOU TO THE MEETING. 

(Subject to Revision.) 

Presented at the XVIlIth Meeting, Scranton, 1888. 
American Society of Mechanical Engineers. 
Advance sheets from Vol. X. Transactions. 

CCCXX. 

SOME TESTS OF THE STRENGTH OF CAST IRON MADE 
IN THE LABORATORY OF APPLIED MECHANICS 
OF THE MASSACHUSETTS INSTITUTE OF TECH- 
NOLOGY. 

BY GAETANO LANZA 

(Member of the Society.) 

WITH HEYWOOD COCHRAN, JOHN K. BURGESS, MAURICE A. VIELE, HENRY F. EASTMAN, AND 

WM. H. GERIUSH. 

The object of this paper is to give a brief account of several sets 
of tests upon the strength and other resisting properties of cast 
iron, carried on in the laboratory of Applied Mechanics of the 
Massachusetts Institute of Technology, of which the results are, it 
is believed, of sufficient practical value to render them worthy of 
record. 

The experiments referred to have formed the subjects of three 
graduating thesis, viz. : 

1st. An investigation upon the modulus of elasticity and some 
other properties of cast iron, by Hey wood Cochran of the class 
of 18S5. 

2d. An investigation of the tensile and the transverse strengths 
of cast iron, and a comparison of their respective moduli of elas- 
ticity, by John K. Burgess and Maurice A. Yiele, of the class of 
1886. 

3d. Experiments upon pulleys, keys and set screws, by Henry F. 
Eastman and William H. Gerrish, of the class of 1888. 

The first portion of the work relates especially to the modulus ot 
elasticity, and the limit of elasticity of common cast iron, both 
planed and unplaned, and of gun iron. 



B-f^^ 



2 TESTS OF THE STRENGTH OF CAST IRON. ^\ o 

The main portion of the experiments, however, are upon the 
transverse strength of cast iron wlien used in the forms of window 
lintels and of pulleys. 

The reason for undertaking these tests was, that it is well known 
that the modulus of rupture of cast iron varies greatly, accoiding 
to the form of the casting, and the manner of using it ; and it was 
considered desirable to obtain some experimental results which 
should be applicable to the forms mentioned. 

Some experiments were also made upon the strength of keys of 
cast iron, wrought iron, and steel, and upon the holding power of 
set screws, all of which are recorded here. 



Summary or the Fikst Set of Experiments — by Mr. Heywood 

Cochran. 

The object of the thesis was to determine the values of the mod- 
ulus of elasticity, and of the limit of elasticity of certain kinds of 
common cast iron, and of gun iron, and of re-testing the specimens. 

The common iron consisted of a half-and-half mixture of Lake 
Superior magnetic and Harrington irons, the last being made from 
an English bog ore. 

The gun iron consisted of a half-and-half mixture of Muirkirk, 
Md., and remelted Salisbury irons. 

The chemical analyses as far as determined were as follows: 

Gun Iron. Common Iron. 

% % 

Total carbon 3.51 

Graphite 2.80 

Sulphur 0.133 0.173 

Phosphorus 0.155 0.413 

Silicon 1.140 1.89 

The test specimens, all of which were cast at the South Boston Iron 
Foundry, were twenty-six inches long and square in section : those 
tested with the skin on being very nearly one inch square, and those 
tested with the skin removed being cast nearly one and one- 
quarter inches square, and afterwards planed down to one inch 
square. 

All were of the same section throughout their entire length. 

The tables of tests will now be given : 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 1. 

Unplaxed Common Ibon. 

Gauged length, 13 ".3125. 

Area of section, 1.0455 square inches. 



Loads Applied. 


Elongations, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1,000 


0.0004 




18,148,370 


1,500 


0.0008 




16,977,500 


2,000 


0.0012 




16,608,450 


500 




0.0000 




2,500 


0.0017 




15,433,500 


3,000 


0.0023 




14,148.000 


3,500 


0.0028 




13,890,720 


500 




0.0002 




4,000 


0.0032 




13,926,800 


4,500 


0.0036 




14,148,000 


5,000 


0.0042 




13,807,000 


500 




0.0004 




5,500 


0.0048 




13,344,800 


500 




0.0004 




6,000 


0.0052 




13,533,540 


500 




0.0004 




6,500 


0.0057 




13,521,90C 


6,500 


0.0056 






500 




0.0004 




7,000 


0.0061 




13,568,140 


500 




0.0006 




7,500 


0.0066 




13,504,800 


500 




0.0008 





Tensile strength, 23,000 lbs. per sq. inch. 

With a load of 11,000 lbs. the piece broke unexpectedly in the 
upper clamps, due to the fact that these clamps did not bind the 
piece as they should have done, but rather pinched it at its lower 
end. Then, too, the load was very suddenly applied. Upon re-test- 
ing, the piece broke with a load of 24,000 lbs., or 23,000 lbs. per 
square inch. A load of 6,500 lbs. was left on for seventeen hours 
and a half without producing any additional elongation. The 
position of the fracture was just outside the upper clamps. 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 2. 

UNPLANED COMMON IRON. 

Gauged length, 13". 5938. 
Area of section, 1.0754 square inches. 



Loads Applied, 


Elongation, Inches. 


Sets, Inches. . 


E. 


500 


0.0000 






1,000 


0.0004 




18,058,140 


1,500 


0.0007 




18,058,140 


2,000 


0.0011 




17,2^7,310 


2,500 


0.0015 




16,854,260 


3,000 


0.0020 




16,206,000 


3,500 


0.0025 




15,168,840 


4,000 


O.OOBO 




14,997,430 


4.500 


0.0034 




15.093,361 


5,000 


0.0039 




14,585,430 


500 




0.0000 




5,500 


0.0046 




13,739,900 


6,000 


0.0050 




13,904,800 


6,500 


0.0057 




13,306,000 


500 




0003 




7,000 


0.0063 




13,146,330 


7.500 


0.0069 




12,917,500 


500 




0.0005 




8,000 


0.0075 




12,640,700 


500 




0.0006 




8,500 


0.0082 




12,408,040 


500 




0.0005 




9.000 


0.0095 






'500 




0.0009 





Tensile strength, 23,000 lbs. per square inch. 

TEST NO. 3. 

TJNPLANED COMMON IRON. 

Gauged length, 13". 4883. . 
Area of section, 1.0614 square inches. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0004 




18,154,300 


1,500 


0.0008 




16,898,300 


2,000 


0.0012 




15,561,000 


2,500 


0.0017 




14,950,600 


3.000 


0.0022 




14,607,000 


3,500 


0.0026 




14,523,460 


4,000 


0.0031 




14,347,800 


4.500 


0.0037 




13,926,600 


5,000 


0.0042 




13,615,800 


500 




0.0001 




5,500 


0.0050 




12,771,900 



At the end of the test a load of 9,000 lbs. was left upon the 
piece for seventy hours. 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 4. 

SAME SPECIMEJS RB-TESTED. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0003 




19,550,800 


1,500 


0.0007 




18,154,300 


2,000 


0.0011 




17,732.140 


2,500 


0.0015 


._ 


17,528,300 


3.000 


0.0019 




16,721,100 


3,500 


0.0023 




16,575,700 


4,000 


0.0029 




15,606,350 


4,500 


0.0035 




14,784,000 


5,000 


0.0040 




14,386,450 


5.500 


0.0048 




13,237,530 


500 




0.0002 




6,000 


0.0052 




13,376,850 


6,500 


0.0058 




13,146,240 


500 




0.0002 




7,000 


0.0062 




13,322.900 


7.500 


0.0066 




13,478.200 


500 




0.0001 




8,000 


0.0071 




13,414,000 


8,500 


0.0076 




13,376,900 


500 




0.0001 




9,000 


0.0081 




13.335,600 


9,500 


0.0086 




13,299,100 


500 




0.0001 




10,000 


0.0093 




13,021,470 


500 




0.0002 




10,500 


0.0100 




12,771,900 


500 




0.0003 





The load of 5,500 lbs. was left upon the piece for two hours. 
At the end of this test a load of 12,000 lbs. was left upon the 
piece, this being above the limit of elasticity. 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 5. 

SAME PIECE RE-TESTED A SECOND TIME. 



Loads Appfied. 


Elongation, luches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0004 




14,950,630 


1,500 


0.0009 




14,950,630 


3,000 


0.0013 




14,950,630 


3,500 


0.0017 




14,734,000 


3,000 


0.0023 




14,606,900 


3,5C0 


0.0037 




14,386,450 


4,000 


0.0032 




14,120,030 


4,500 


0.0037 




13,926,640 


5,000 


0.0043 




13,779,800 


5,500 


0.0047 




13,664,540 


6,000 


0.0053 




13,571,700 


6,500 


0.0057 




13,376,900 


7,000 


0.0063 




13,333,900 


7,500 


0.0067 




13,337,670 


8,000 


0.0073 




13,146,330 


8,500 


, 0.0078 


• ■ 


13,993,535 


9,000 


0.0084 




13,859,330 


9,500 


0.0090 




13,708.000 


10,000 


0.0095 




13,708,000 


10,500 


0.0101 




13,613,430 


11,000 


0.0107 




13,499,700 


500 




0.0003 




11,500 


0.0111 




13,593 540 


12,000 


0.G117 




13,490,800 


12,500 


0.0134 




13,298,000 


500 




0.0007 




13,000 


0.0130 




13,366,430 


500 




0.0009 





Tensile strength, 20,200 lbs. per square inch* 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 6. 

UNPLANED GCN IKON. 

Gauged Length, 13. "5625 
Area of section, 1.0506 sq. inch. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E 


500 


0.0000 






1.000 


0.0003 




21,505,580 


1,500 


0.0007 




18,441,850 


2.000 


0.0011 




18,441,850 


2,500 


0.0015 




17,805,920 


3,000 


0.0019 




17,445,000 


3,500 


0.0023 




17,212,400 


4,000 


0.0027 




17,050,000 


4,500 


0.0031 




16,930,200 


5,000 


0.0036 




16,363,900 


500 


0. 


0.0001 




5,500 


0.0041 




15,937,400 


6,000 


0.0046 




15.435,000 


6,500 


0.0050 




15,491,150 


7.000 


0.0055 




15,256,440 


500 




0.0005 




7,500 


0.0060 




15,187,400 


500 




0.0005 




8,000 


0.0063 




15,368,480 


500 




0.0005 




8.500 


0.0068 




15,192,300 


9,000 


0.0074 




14,929,830 



Tensile strength, 27,000 lbs. per sq. in. 

The piece broke first with a load of 18,900 lbs., exhibiting a bad 
flaw, and then, upon being re-tested broke at 28,450 lbs., or about 
27,000 lbs. per sq. inch, as given above. 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 7. 

TJNPLANED GUN IRON. 

Gauged length, 13."3906. 
Area of section, 1.0630 sq. in, 



Loads applied. 


Elongation, inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


O.O0O3 




22,903,620 


1,500 


0.0005 




23,994,300 


2,000 


0.0008 




22.903,620 


2,500 


0.0012 




21,907,800 


3,000 


0.0016 




20,316,700 


3,500 


0.0020 




19,380,000 


4,000 


0.0024 




18,761,470 


4,500 


0.0027 




18,662,200 


5,000 


0.0031 




18,286,000 


5,500 


0.0035 




18,125,160 


6,000 


0.0039 




17,995,300 


6,500 


0.0043 




17,680,000 


7,000 


0.0047 




17,421,370 


7,500 


0.0051 




17,205,540 


8,000 


0.0055 




17,177,700 


500 




0.0000 




8,500 


0.0059 


. 


17,080,670 


9,000 


0.0064 




16,862,100 


500 




0.0000 




9,500 


0.0068 




16,672,500 


10,000 


0.0072 




16,621,370 


500 




0.0001 




10,500 


0.0078 




16,254,180 


11,000 


0.0082 




16,130,300 


500 




0.0003 




11,500 


0.0087 




16,019,300 


500 




0.0003 




13,000 


0.0092 




15,746,240 


500 




0.0005 




12,500 


0.0098 




15,504,000 


500 




0.0007 




13,000 


0.0135 




15,213.760 


500 




0.0008 





A load of 13,250 lbs. remained upon this piece for seventeen 
hours, this load being just above the elastic limit. 



TESTS OF THE STRENGTH OF CAST IRON. 
TEST NO. 8. 

SAME SPECIMEN RE-TESTED. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E. 


500 


0.0000 






1,000 


00008 




20,995,000 


1,500 


• 0.0006 




20,995,000 


2,000 


0.0009 




20,427,550 


2,500 


0.0013 




19,760.000 


8,000 


0.0017 




19,076.300 


3,500 


0.0021 




18,212,500 


4,000 


0.0025 




17,995,700 


4,500 


0.0028 




17.886,440 


5,000 


0.0032 




17,714,500 


5,500 


0.0036 




17,495,820 


6,000 


0.0040 




17,429.800 


6,500 


0.0044 




17,275,870 


7,000 


0.0048 




17,147.750 


7,500 


0.0052 




16,876.850 


8,000 


0.0056 




16,796,000 


5U0 




0.0000 




8,500 


0.0061 




16,588,250 


9,000 


0.0065 




16,536,580 


9,500 


0.0069 




16,490,600 


10,000 


0.0073 




16,449,700 


500 




0.0002 




10,500 


0.0077 




16,306,800 


11,000 


0.0081 




16,279,200 


500 




0.0002 




11,500 


0.0085 




16,254,180 


12,000 


0.0089 




16,231.410 


12,500 


0.0093 




16,210,600 


13,000 


0.0098 




16,108,680 


500 




0.0002 




13,500 


0.0102 




16,094,430 


14,000 


0.0108 




15,782,750 


14,500 


0.0112 




15,711,200 


500 




0.0003 




15,000 


0.0118 




15,446,600 


500 




0.0005 




16,000 


0.0130 







A load of 16,000 lbs. was left upon the piece for 22 hours. 



10 



TESTS OF THE STBENGTH OF CAST IRON. 



r : r TEST NO. 9. 

SAME SPECIMEN RE-TESTED A SECOND TIME. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches, 


E 




500 


0.0000 








1,000 


0.0003 




19,380,000 




1,500 


0.0006 




20,156,200 




2,000 


0.0009 




20,427.550 




2,500 


0.0012 




20.995,000 




3,000 


0.0016 




20,317,700 




3,500 


0.0019 




19,681,700 




4,000 


0.0023 




19,169,300 




4,500 


0.0028 




18,323,000 




5,000 


0.0032 




17.995,700 




5,500 


0.0035 




17,868,100 




6,000 


0.0039 




17,995,700 




6,500 


0.0043 




17,784,000 




7.000 


0.0047 




17,703,890 




7,500 


0.0050 




17,548,000 




8,000 


0.0054 




17,495,820 




* 8,500 


0.0058 




17.450,400 




9,000 


0.0062 


* 


17,420,450 




9,500 


0.0065 




17,375,160 




10,000 


0.0071 




16,974,670 




10.500 


0.0075 




16,796,000 




11.000 


0.0080 




16.637,530 




11,500 


0.0084 




16,545.300 




500 




0.0000 


16,415,340 




12,000 


0.0088 








12,500 


0.0093 




16,342,042 




13,000 


0.0097 




16,233,240 




13,500 


0.0102 




16,134,100 




14.000 


0.0106 




16,043,300 




500 




0.0002 






14,500 


0.0111 




15.960,000 




15,000 


0.0115 




15.883,000 




15,500 


0.0120 




15,779,100 




16,000 


0.0125 




15,620.300 




500 




0.0001 






16,500 


0.0130 




15,504,000 




500 




0.0001 







Tensile strength, 28,750 lbs. per sq. inch. 

This piece broke first with a load of 27,100 lbs., exhibiting a 
flaw ; upon being re-tested it broke with 30,450 lbs., or 28,750 lbs. 
per sq. inch 



TESTS OF THE STRENGTH OF CAST IRON. 



11 



TEST NO. 10. 

UNPLANED GUN IRON. 

Gauged length, 13".4844. 
Area of section, 1.0620 sq. in. 



Loads Applied, 


Elongation, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1,000 


0.OCO3 




21,168,200 


1,500 


0.0006 




22,088,600 


2,000 


0.0009 




21,773,000 


2,500 


0.0012 




21,618,6:^0 


3,000 


0.0015 




20,821,220 


3,500 


0.0019 




20,054,100 


4,000 


0.0023 




19,757,020 


4,500 


0.0027 




18,816,200 


5,000 


0.0031 




18,586,800 


5,500 


0.0035 




18,184,200 


6,000 


0.0040 




17.684,900 


6,500 


0.0044 




17,518,545 


7,000 


0.0048 




17,380,200 


7,500 


0.0052 




17,180,000 


500 




0.0001 




8,000 


0.0057 




16,859,700 


8,500 


0.0061 




16,657,000 


500 




0.0002 





Tensile strength, 28,775 lbs. per sq. inch. 
The piece broke first at 23,000 lbs., exhibiting a flaw, and on 
being re-tested it broke at 30,550 lbs., or 28,775 lbs. per sq. inch. 

TEST NO. 11. 

PLANED COMMON IRON. 

Gauged length, 13". 5274. 
Area of section, 0.9937 sq. in. 



Loads Applied, 


Elongation, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1,000 


0.0004 




17,016,454 


l,.iOO 


0.0009 




15,125,737 


500 




0.0000 




2,000 


0.0014 




14,585,532 


2,500 


0.0021 




12,964,917 


3,000 


0.0028 




12,154,610 


500 




0.0002 




3,500 


0.0032 




12,762,340 


4,000 


0.0040 




11,911,517 


500* 




0.0004 




4,500 


0.0044 




12,375,603 


5110 




0.0015 




5,000 


0.0049 




12,501.885 


500 




0.0015 




5.500 


0.0056 




12.154,610 


500 




0.0015 




6,000 


0.0064 




11,698,812 


500 




0.0018 




6,500 


0.0068 




12,011,614 


500 




0.0019 





A load of 10,000 lbs. was left upon this piece over night. 



* Tightened the clamps. 



12 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 12. 

SAME SPECIMEN RE-TESTED. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1,000 


0.0004 




18,150,700 


1,500 


0.0010 




14.329,500 


2,000 


0.0016 




13,173,900 


2,500 


0.0021 




12,81'^,300 


500 




- 0.0001 




3,000 


0.0029 




11,941,250 


3,500 


0.0034 




12.039,200 


4,000 


0.0039 




12,216,800 


500 




0.0000 




4,500 


0.0045 




12,236,430 


500 




- 0.0001 




5,000 


0.0051 




12,070,700 


500 




0.0000 




5,500 


0.0059 




11,685,100 


500 




0.0001 




6,000 


0.0064 




11,790,600 


500 




O.OCOl 




6,500 


0.0071 




11,585.600 


500 




0.0000 




7,000 


0.0078 




11,344,200 


500 




0.0000 




7,500 


0.0085 




11,243,800 


500 




0.0000 




8,000 


0.0093 




11,037,600 


500 




0.0001 




8,5<i0 


0.0098 




11,169,680 


500 




0.0001 




9,000 


0.0106 




10,890,430 


500 




0.0003 




9,500 


0.0112 




10,939,000 


500 




0.0003 




10,000 


0.0121 




10,732,250 


500 




0.0004 




, 10,500 


0.0129 




10,593,800 


500 




0.0006 




11,000 


0.0139 




10,320,350 


500 




0.0006 




11,500 


0.0148 




10,100,730 


500 




0.0009 




12,000 


0.0157 




9,971,330 


500 




0.0013 





A load of 14,000 lbs. was left upon this piece over night. 



TESTS OY THE STRENGTH OF CAST IR N. 



13 



TEST NO. 18. 

SAME SPECIMEN RE-TESTED A SECOND TIME. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E. 


500 


0.0000 






1.000 


0.0005 




13,613,040 


1,500 


0.0011 




12,U64,800 


2,000 


0.0G17 




12,375,500 


2,500 


0.0024 




11,585,540 


3,000 


0.0029 




11,635,100 


3,500 


0.0035 




. 11,585,540 


4,000 


0.0042 




11,480,900 


4,500 


0.0048 




11,463,000 


5,000 


0.0054 




11,344,200 


5,500 


0.0061 




11,-250,440 


6,000 


0.0067 




11,216,730 


6,500 


0.0075 




10,900,460 


7,000 


0.0082 




10,790,810 


7,500 


0.0091 




10,529,420 


8,000 


0.0097 




10,498,500 


500 




0.0001 




8,500 


0.0105 




10,421.500 


9,000 


0.0112 




10,377.650 


9,500 


0.0119 




10,274,000 


10,000 


0.0128 




10,151,000 


500 




0.0002 




10,500 


0.0135 




10.121,200 


11,000 


0.0143 




10,030,500 


500 




0.0002 




11,500 


0.0151 




9,936,500 


12,000 


0.0160 




9,789,680 


500 




0.0003 




12,500 


0.0170 




9,637.5:0 


500 




0.0004 




13,000 


0.0178 




9,586,642 


500 




0.0004 




13,500 


0.0185 




9,591,840 


500 




0.0005 




14,000 


0.0192 




9,589,220 


500 




0.0006 




14.500 


0.0206 




9,270,480 


500 




0.0010 





Tensile strength, 20,800 lbs. per sq. 



in. 



14 



TESTS OF THE STRENGTH OF OAST IRON. 



TEST NO. 14. 

PLANED COMMON IRON. 

Gauged length, 13. "461. 
Area of section, 0. 9852 sq. in. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E. 


500 


0.0000 






1,000 


0.0004 




19,518,890 


1,500 


0.0008 




18,217,600 


2,000 


0.0012 




17,071,150 


2,500 


0.0018 




15,615,100 


3,000 


0.0024 




14,232,000 


3,500. 


0.0030 




13,663,200 


500 




0.0000 




4,000 


0.0037 




12,837,900 


4,500 


0.0043 




12,710,000 


500 


, 


0.0002 




5,000 


0.0048 




12,742,900 


500 




0.0002 




5,500 


0.0054 




12,769,360 


500 




0.0004 




6,000 


0.0060 




12,629,900 


500 




0.0009 




• 6,500 


0.0068 




12,145,100 


500 




0.0010 




7,000 


0.0075 




11,802,000 


500 




0.0011 




7,500 


0.0083 




11,628,300 


500 




0.0013 




8,000 


0.0089 




11,481,700 


500 




0.0014 




8,500 


0.0096 




11,386,000 


500 




0.0018 




9,000 


0.0102 




11,430,200 


500 




0.0019 




9,500 


0.0115 




11,028,600 


500 




0.0021 




10,000 


0.0122 




10,661,250 


500 




0.0023 





TESTS OF THE STRENGTH OF CAST IRON. 



15 



TEST NO. 15. 

SAME SPECIMEN EE-TESTED. 



Loads applied 


Elongation, inches. 


Sets, incheB. 


E. 


500 


0.0000 




' 


1,000 


0.0004 




18,217,400 


1,500 


0.0008 




17,630.000 


2,000 


0.0013 




16,777,700 


2,500 


0.0018 




14,973,400 


3,000 


0.0024 




14,085,46; 


3,500 


0.0031 




13,439,24( 


4,000 


0.0036 




13,101,26( 


4,500 


0.0043 




12,935,59( 


5,000 


0.0048 




12,809,27c 


500 




-0.0001 




5,500 


0.0055 




12,421,100 


6,000 


0.0061 




12,319,300 


500 




0.0000 




6,500 


0.0067 




12,190,230 


7,000 


0.0074 




13,083,110 


7,500 


0.0U81 




11,855,300 


8.000 


0.0088 




11,600,850 


500 




-0.0001 




8,500 


0.0096 




11,356,700 


9,000 


0.0103 




11,348,170 


9,500 


0.0110 




11,153,450 


500 




0.0000 




10,000 


0.0119 




10,930,510 


500 




0.0001 




10,500 


9.0129 




10,613,200 


500 




0.0003 




11,000 


0.0139 




10,331,150 


500 




0.0005 




11,500 


0.0148 




10,138,000 


500 




0.0007 




12,000 


0.0163 




9,714,190 



16 



TESTS OF THE STBENGTH OF CAST IR N. 



TEST NO. 16. 

SAME SPECIMENS KE-TESTED A SECOND TIME. 



Loads, Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0005 




13,663,220 


1,500 


0.0012 




11,881,090 


2,000 


0.0017 




12,421,100 


2,500 


0.0023 




12,145,100 


3,000 


0.0028 




12,191,340 


3,500 


0.0035 




11,881,090 


4,000 


0.0043 




11,252,060 


4,500 


0.0050 




10,930,600 


6,000 


0.0056 




10,979,370 


500 




0.0001 




5,500 


0.0063 




10,930,600 


6,000 


0.0070 




10,812,620 


6,500 


0-0077 




10,646,700 


7,000 


0.0084 




10,572,730 


500 




0.0002 




7,500 


0.0090 




10,626,950 


8,000 


0.0097 




10,564,340 


8,500 


0.0104 




10,510,160 


9,000 


0.0111 




10,486,400 


500 




0.0001 




9,500 


0.0118 




10,465,440 


10,000 


0.0125 




10,425,750 


10,500 


0.0132 




10,331,350 


11, (.00 


0.0140 




10,247,410 


500 


• 


0.0001 




11.500 


0.0149 




10,086,900 


12,000 


0.0158 




9,976,310 


500 




0.0002 




12,500 


0.0164 




10,012,735 


500 




0.0001 




13,000 


0.0174 




9,843,800 


500 




0.0002 




13,500 


0.0182 




9,759,440 


500 




0.0002 




14,000 


0.0191 




9,682,590 


500 




0.0005 




14,500 


0.0202 




9,480,5" 


500 




O.OOIO 





Tensile strengtli, 20,300 lbs. per square incli. 



TESTS OF THE STRENGTH OF CAST IRON. 



17 



TEST NO. 17. 

PLANED COMMON IRON. 

Gauged length, 13". 582. 

Area of section, 0.996 square inches. 



Loads, Applied. 


Elongation, Inches. 


Sets, Inches, 


E. 


500 


0.0000 






1,000 


0.0005 




15,151,720 


1,500 


0.0009 




lG,G54,0p0 


2,0(i0 


0.0014 




14,6^0,600 


2,500 


0.0019 




14.854,260 


3,000 


0.0025 




13,636,550 


• 3,500 


0.0032 




12,987,200 


4,000 


0.0037 




12,899,440 


500 




0.0000 




4,500 


0.0044 




12.114,810 


5,000 


0.0051 




11,973,550 


5,500 


0.0059 




11,605.570 


6,000 


0.0066 




11,363,800 


500 




0.0006 




6,500 


0.0071 




11,605,570 


7,000 


0.0078 




11,437,100 


500 




0.0008 




7,500 


0.0084 




11,429,200 


500 




0.0010 




8.000 


0.0091 




11,238,900 


500 




0.0014 




8,500 


0.0102 




10,748,000 


500 




0.0016 


■ 


9,000 


0.0109 




10,634,000 


500 




0.0018 




9,500 


0.0116 




10,580,080 


500 




0.0021 




10,000 


0.0123 




10,575,300 



18 



TESTS OF THE STBENGTH OF CAST IRON. 





TEST 


NO. 18. 






THE SAME 


RE-TESTED. 




Loads. Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0005 




15,151,720 


1,500 


0.0009 




15,151,720 


2,000 


0.0014 




15,151,720 


2,500 


0.0019 




14,742.215 


3,000 


0.0024 




14,204,740 


3,500 


0.0030 




13,867,700 


4,000 


0.0036 




13,444,480 


4,500 


0.0042 




13,143,660 


5,000 


0.0049 




12,523,360 


500 




-0.0001 




5,500 


0.0056 




12,285,200* 


6,000 


0.0063 




12,000,170 


500 




-0.0002 




6,500 


0.0070 




11,688,500 


7,000 


0.0077 




11,586,600 


500 




-0.0002 




7,500 


0.0084 




11,431,840 


8,000 


0.0092 




11,177,500 


500 




-0.0002 




8,500 


O.0099 




11,019,430 


500 




-9.0002 




9,000 


0.0106 




10,935,000 


500 




-0.0001 




9,500 


0.0114 




10,813,120 


500 




-0.0001 




10,000 


0.0121 




10,706,130 


500 




0.0001 




10,500 


0.0129 




10,611,860 


500 




0.0002 




11,000 


0.0139 




10,301,000 


500 




0.0005 




11,500 


0.0150 




10,000,000 


500 




0.0009 




12,000 


0.0162 




9,710,230 



TESTS OF THE STRENGTH OF CAST IRON. 



19 



TEST NO. 19. 

SAME SPECIMEN BE-TESTED A SECOND TIME. 



Loads applied. 


Klongation, inch«-8. 


Sets, inches. 


E. 


COO 


0.0000 






1,000 


0.0006 




13,396,900 


1,500 


0.0011 




12,987,200 


2,000 


0.0017 




12.396,900 


2,500 


0.0023 




12,121,380 


3,000 


0.0029 




11,755,600 


3;500 


0.0035 




11,688,500 


4,000 


0.0041 




11,640,900 


4,500 


0.0048 




11,483,400 


5,000 


0.0054 




11,363,800 


5,500 


0.0061 




11,288,520^ 


G,000 


0.00G8 




11,029,560 


6.500 


0.0076 




10,837,01)0 


7,000 


0.0083 




10,679,200 


7,500 


0.0091 




10,587,600 


8,00ii 


0.0098 




10,424,120 


500 




0.0000 




8,500 


0.0105 




10,437,050 


9,000 


0.0114 




10,212,400 


500 




0.0000 




9,500 


0.0121 




10,198,700 ' 


10,000 


0.0129 




10,042,400 . 


500 




0.0.000 


, 


10,500' 


0.0138 




9,9,17,490 


500 




0.0000 




11,000 


0.0146 




9,840,810 


500 




0.0001 




11,500 


0.0153 




9,836,200 


500 




0.0002 




: 12.000 


0.0160 




9,832,000 


500 




0.0001 




12,500 


0.0171 




9,597,570 


500 




0.0001 




13,000 


0.0178 




9,576,230 


500 




0.0002 




13,500 


0.0189 




9,379,640 


500 




0.0004 




14,000 


0.0198 




9,279,650 



Tensile strength, 20,450. 



20 



TESTS OF TJIE STRErNGIH OF CAST IRON. 



TEST NO. 20. 

PLANED GUN IRON. 

Gauged length, 13. "2774 
Area of section, 1.0028 sq. in. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E. 


500 


0.0000 






1,000 


0.0004 




18,879,100 


1,500 


0.0007 




18,879,100 


2,000 


0.0011 




18,055,000 


2,500 


0.0015 




17,008,000 


3,000 


0.0019 




17,195,100 


3,500 


0.0024 




16,724,600 


* 4,000 


0.0028 




16,403,950 


4,500 


0.0033 




16,171,410 


5,000 


0.0038 




15,888,400 


500 




0.0002 




5,500 


0.0041 




16,048,900 


6,000 


0.0046 




16,004,800 


6,500 


0.0050 




15,888,400 


7,000 


'0.0055 




15,791,200 


500 




0.0002 




7,500 


0.0059 




15,642,550 


500 




0.0002 




8.000 


0.0066 




15,150,680 


8,500 


0.0070 




15,240,680 


500 




0.0007 




9,000 


0.0073 




15.523,100 


9,500 


0.0077 




15,576,800 


500 




0.0007 




10,000 


' 0.0C81 




15,529,800 


500 




0.0008 




10,500 


0.0086 




15,395,800 


500 




0.0009 




11,000 


0.0091 




15,277,300 


500 




0.0009 




11,500 


0.0097 




15,092,600 


500 




0.0011 




12,000 


0.0102 




15,075,600 


500 




0.0013 





Tensile strength, 29,500. 



TESTS OF THE STRENGTH OF CAST IRON. 



21 



TEST NO. 21. 

SAME SPECIMEN RE-TESTED. 



Loads applied. 


Elongation, inches. 


Sets, inches. 


E. 


500 


0.0000 






1,000 


0.0004 




17,653,780 


1,500 


0.0008 




17,658.780 


2,000 


0.0012 




17.270,000 


2,500 


0.0016 




17,084,820 


3,000 


0.00-20 




16,974,800 


3,500 


0.0024 




16,550.400 


4,000 


0.0029 




16,2(10,000 


4,500 


0.0033 




16,295,H00 


5,000 


0.0037 




16,828,700 


5,500 


0.0041 




16,146,740 


500 




0.0000 




6,000 


0.0046 




16,004,800 


6,500 


0.0050 




15,888,400 


7,000 


0.0055 




15,792,600 


7,500 


0.0059 




15,708,860 


500 




0.0001 , 




8,000 


0.0064 




15,576,850 


8,500 


0.0069 




15,468,150 


9,000 


0.0073 




15,469,800 


500 




0.0001 




9,500 


0.0078 




15,277,660 


10.000 


0.0083 




15,246,440 


10,500 


0.0087 




15,218,770 


500 




0.0002 




11,000 


0.0092 




15,111,200 


11,500 


0.0097 




15,014,800 


500 




0.0002 




12.000 


0.0102 




14,927,800 


12,500 


0.0107 




14,849,000 


500 




0.0004 




18,000 


0.0113 




14,711,480 


18,500 


0.0117 




14,711,480 


500 




0.0004 




14,000 


0.0122 




14,711,480 


14,500 


0.0128 




14,481,600 


500 




0.0006 





22 



TESTS OF THE STBENGTH OF CAST IBON. 



TEST NO. 22. 

SAME SPECIMEN RE-TESTED A SECOND TIME, 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0004 




17,653,900 


1,500 


0.0008 




17,653,900 


2,000 


0.0012 




17,653,900 


2,500 


0.0016 




17,084,300 


3,000 


0.0020 




16,759,900 


3,500 


0.0024 




16,550,410 


4,000 


0.0028 




16,404,000 


4,500 


0.0033 




16,295,800 


5,000 


0037 




15,995 000 


5,500 


0.0042 




15.856,700 


6,000 


0.0046 




15,827,200 


6,500 


0.0051 




15,658,600 


7,000 


0.0056 




15,506,700 


500 




0.0005 




7,500 


0.0061 




15,319,400 


8,000 


0.0065 




15,395,700 


8,500 


0.0068 




15,576,890 


9,000 


0.0072 




15,740,300 


9,500 


0.0076 




15,783,170 


10,000 


0.0080 




15,722,900 


500 




0.0001 




10,500 


0.0088 




15,131,800 


11,000 


0.0093 




15,029,600 


11,500 


0.0098 




14,937.800 


12.000 


0.0103 




14,855,000 


500 




0.0001 




12,500 


0.0109 




14,644,000 


13.000 


0.0113 




14.646,720 


13,500 


0.0118 




14,586,800 


500 




0.0002 




14,000 


0.0123 




14.532,090 


14,500 


0.0128 




14,152,000 


500 




0.0002 




15,000 


0.0134 




14,327,220 


500 




0.0002 




15,500 


0.0140 




14,160,780 


500 




0.0003 




16.000 


0.0146 




14,056,500 


500 




0.0004 




16,500 


0.0152 




13,937,200 


500 




0.0006 




• 17,000 


0.0158 




13,870,800 


500 




0.0009 





Tensile strength, 29,500. 



TESTS OF THE STRENGTH OF CAST IBON. 



23 



TEST NO. 23. 

PLANED GUN IRON. 

Gauged length, 13.508 inches. 

Area of section, 0.9930 square inches. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0003 




20,927,000 


1.500 


0.0007 




20,927,000 


2,000 


0.0010 




20,404,350 


2,500 


0.0014 




19,780,500 


3,000 


0.0018 




19,433,200 


3,500 


0.0021 




19,204,560 


4,000 


0.0025 




18,856,000 


4,500 


0.0080 




18.602,700 


5.000 


0.0034 




18,273,000 


500 




0.0000 




5,500 


0.0039 




17,440,000 


6.000 


0044 




17,199,500 


6.500 


0.0048 




17,004.000 


7,000 


0.0053 




16,684,000 


500 




0.0000 




7.500 


0.0057 




16,632,800 


8.000 


0.0062 




16,455,550 


8.500 


0.0067 




16,242,650 


500 




0.0002 




9,000 


0.0071 




16,228,400 


9,500 


0.0077 




16,003.800 


500 




0.0004 




10,000 


0.0081 




16,053,500 


500 




0.0005 




10,500 


0.0087 




15,726,270 


500 




0.0007 




11,000 


0.0090 


, 


15,870,430 


500 




0.0009 




11,500 


0.0095 




15,834,450 


500 




0.0012 




12,000 


0.0099 




15,881,940 



24: 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST No. 24. 

SAME SPECIMEN RE-TESTED. 



Loads Applied. 


Elongation, Inches, 


Sets, Inches. 


E. 


500 


0.0000 






1,000 


0.0004 




19,433,200 


1,500 


0.0007 




18,763,070 


2,000 


0.0011 


' 


18,549,900 


2,500 


0.0016 




17,552,550 


500 




0.0001 




3.000 


0.0020 




17,219,270 


3,500 


0.0024 




17,004,030 


4,000 


0.0029 




16,705,700 


4,500 . 


0.0038 




16,488,760 


5,000 


0.0038 




16,323,860 


5,500 


0.0042 




16,194,300 


6,000 


0.0047 




16,089,900 


6,500 


0.0051 




16,003,800 


7,000 


0.0056 




15,931,740 


7,500 


0.0060 




15,870,430 


8,000 


0.0065 




15,817,700 


500 




0.0001 




8,500 


0.0070 




15,858,400 


9,000 


0.0074 




15,625,330 


9,500 


0.0079 




15,596,053 


10,000 


0.0083 




15,569,950 


500 




0.0002 




10,500 


0.0088 




15,546,540 


11,000 


0.0092 




15,525,420 


11,500 


0.0097 




15,426,340 


500 




0.0004 




12,000 


0.0101 




15,527,250 


500 




0.0004 




12,500 


0.0106 




15,472,900 


500 




0.0005 




13,000 


o.mio 




15,459.200 


500 




0.0005 




13,500 


0.0116 




15,311,000 


500 




0.0006 




14,000 


0.0121 




15,240,130 



TESTS OF THE STBENGTH OF CAST IRON. 



9r. 



TEST NO. 25 

SAME SPECIMEN RE-TESTED A SECOND TIME. 



Loadi* Applied. 


Elongation, Inches. 


Sets, Inches. 


E 


500 


O.OCOO 






1,000 


0.0004 




18,137,700 


1,500 


0.0008 




18,137,700 


2.000 


0.0012 




17.743,340 


2,500 


0.0016 




17,552,550 


3.000 


0.0020 




17,440,030 


8,500 


0.0028 




17,740,340 


4,0(!0 


0.0027 




17,633,800 


4,500 


0.0031 




17,552,550 


5,000 


0.0035 




17,489.900 


5,500 


0.0040 




17,219,280 


6,000 


0.0044 




17,004.030 


6,500 


0.0049 




16,828.740 


7,000 


0.0053 




16,682,200 


7.500 


0.0058 




16,556,560 


8.000 


0.0062 




16.455,500 


8,500 


0.0067 




16,364,800 


9,000 


0.0071 




16.285.530 


9.500 


0.0076 




16,215,V(iO 


10,000 


0.0080 




16,153,800 


500 




0.0000 




10,500 


0.0085 




16,051,000 


11,000 


0.0089 




15,959,100 


11,500 


0.0094 




15,876,440 


12,000 


0.0099 




15,801,730 


500 




0.0000 




12,500 


0.0105 




15,020,700 


13,000 


0.0112 




15,250,250 


500 




0.0000 




13,500 


0.0118 




14,990,060 


14,000 


0.0123 




14.980,875 


500 




0.0000 




14,500 


0.0128 




14,849,530 


500 




0.0001 




15,000 


0.0133 




14,886,550 


500 




0.0001 




15.500 


0.0188 




14,839,900 


500 




0.0002 




16,000 


0.0143 




14,796,500 


500 




0.0003 




16,500 


0.0149 




14,583,025 


500 




0.0005 




17,000 


0.0156 




14,388,000 



Tensile strength, 31,000. 



26 



TESTS OF THE STRENGTH OF CAST IRON. 



TEST NO. 26. 

PLANED GUN IRON. 

Gauged length, 13". 5274. 
Area of section, 0.99 sq. inch. 



Loads Applied. 


Elongation, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1,000 


0.0003 




21,031,600 


1,500 


0.0007 




21,021,600 


3.000 


0.0010 


k I: 


21,021,600 


2.500 


0.0013 




20,625.000 


3,000 


0.0017 




20,094,200 


3,500 


0.0021 




19,520,050 


4,000 


0.0025 




19,129.700 


4,500 


0.0029 




18,847,000 


5,000 


0.0034 




18,218,320 


500 




0.0000 




5,500 


0.0039 




17,631,020 


6,000 


0.0044 




17,276,4'i0 


6,500 


0.0048 




17,080,000 


7,000 


0.0053 




16,917,400 


7,500 


0.0057 




16,780,400 


500 




0.0001 




8,000 


0.0062 




16,529,100 


8,500 


0.0067 




16,315,300 


500 




0.0003 




9,000 


0.0071 




16,301,000 


9,500 


0.0077 




16,075,320 


500 




0.0004 




10,000 


0.0082 




15,927,400 


500 




0.0006 




10,500 


0.0086 




15,888,420 


500 




0.0007 




11,000 


0.0093 




15,510,530 


500 




0.0009 




11,500 


0.0098 




15,415,850 


500 




0.0010 




12,000 


0.0101 




15,558,060 



TESTS OF THE STRENGTH OF CAST IRON. 



27 





TEST NO. 27. 






SAME SPECIMEN RE-TEBTED. 


• 


Lottds Applied. 


Elongation, Inches. 


Sets, Inches. 


E 


500 


0.0000 






1.000 


0.0004 




19,520.060 


1,500 


0.0007 




19,520.060 


2.000 


0.0011 




19.066,100 


2.500 


0.0015 




18,84(;,1)50 


3.000 


0.0019 




18,218.720 


3,500 


0.0023 




17.88>,670 


4,000 


0.0028 




17.390,000 


4,500 


0.0032 




17,351.170 


5.000 


0.0036 




17,320,600 


5,500 


0.0040 




17,186,710 


500 




0.0001 




6,000 


0.0044 


' 


17,177,500 


6,500 


0.0049 




16,605,935 


7,000 


0.0054 




16,447,460 


7,500 


0.0059 




16,211,940 


8,000 


0.0064 




16,059.445 


500 




0.0002 




8,500 


0.0070 




15.728,400 


9,000 


0.0074 




15,69o,"^00 


9,500 


0.0078 




15,766,200 


500 




0.0002 




10,000 


0.0083 




15.592,600 


10.500 


0.0088 




15,616,050 


11,000 


0.0093 




15,510,540 


500 




0.0002 




11,500 


0.0097 




15,455,471 


12,000 


0.0102 




15,367,850 


500 




0.0t04 




12.500 


0.0106 




15,468,700 


500 




0.0004 




13,000 


OIU 




15,387,440 • 


500 




0.0004 




13,500 


0.0116 




15,280,340 


500 




0.00C4 




14,000 


0.0122 




15,182,270 


500 




0.0005 





Tensile strength, 31,000. 



'28 



TESTS OF THE StREN^GTH OF C iST IRON 



TEST NO. 28. 

SAME SPECIMEN RE-TEfcTED A SECOND TIME. 



Loads Applied. 



Elongation, Inches. 



Sets, Inches 



500 


0.0000 


1,000 


0.0004 


1,5U0 


0.0008 


3.01)0 


0.0012 


2,500 


0.0016 


3,000 


0.0020 


3,500 


0.0025 


4,000 


0.0029 


. 4.500 


0.0034 


5.000 


0.0038 


5,500 


0.00-13 


0,000 


0.0047 


6,500 


0.0052 


7,000 


0.0056 


7,500 


0.0C61 


8,000 


0.0066 


8,500 


0.0070 


9,000 


0.0075 


9,500 


0.0080 


10,000 


0.0086 


500 




10,500 


0.0091 


11.000 


0.0095 


11,500 


O.OIOO 


12,000 


0104 


12,500 


0.0109 


13,000 


0.0114 


13,500 i 


0.0119 


14.000 


0.0124 


14,500 


0-.01.29 


500 




15,000 


0.0134 


15.500 


0.0140 


16,000 


0.0146 


500 




16,500 


0.0152 


17,000 


0.0158 


500 






ensile strength, 31,000 lbs. per square inch. 



18,176,400 
18,176.400 
17,781,700 
17.714.500 
16,830,400 
16,.524.400 
16,312.530 
16,120,000 
16.038,370 
15,907,900 
15.868.650 
15,806,000 
15,753,250 
15,708,360 
15.609,500 
15 524,700 
15,450,300 
15.336.700 
14,999,200 

14,980.900 
15,067,620 
15.071,200 
15,074,530 
15,008.380 
15,013.900 
14.9-)5,600 
14,914,10) 
14,852,750 

14,724,250 
14,580,330 
14,448,250 

14,346,820 
14,259,150 



Frorn these tests Mr. Cochran obtains the following as average 

values for tlie specimens tested, viz.: '^ 

For tensile strength : 

I laned common ' 

Unplanedgun f'^f 

Planedgun... ~^'^^^ 

*= 30,500 



TESTS OF THE STRENGTH OF CAST I HON. 29 

For limit of elasticity : 

Unplaned common 6,500 

Planed common 5,833 

Uuplaned Gun. , 11,000 

Planed Gun 8,500 

For modulus of elasticity at assumed elastic limit : 

Unplaned common 13,194,233 

Planed common 11,943,953 

Unplaned gun 16,130,300 

Planed gun 15,932,880 

Colonel Rosset of the Turin arsenal gave for gun iron, as average 
limit of elasticity 9,800, and as average modulus of elasticity 
16,268,300. 

He attributes the apparent anomaly in the case of gun iron, 
whose average tensile strength is less in the unplaned than in the 
planed, to the presence of surface flaws in the unplaned gun. 

He draws from his tests the following conclusions, viz.: 

1°. Planed pieces stretch more than unplaned. 

2°. The moduli of planed are higher than those of unplaned 
pieces. 

3°. Common iron stretches from ^ to ^ more than gun iron. 

4°. The elastic limit for unplan'ed is higher than that for 
planed. 

5°. The effect of re-testing is to lower the modulus of elasticity, 
to raise the elastic limit, to make the stretch ipore nearly equal on 
the two sides, and probably to lower the tensile strength. 

Summary of the Experiments of Messrs. Burgess and Viele. 

The object of this investigation was to determine the transverse 
strength of cast iron in the form of window lintels, and also the 
deflections under moderate loads, and from the latter to deduce 
the modulus of elasticity of the cast iron, and to compai-e it with 
the modulus of elasticity of the same iron, as determined from 
tensile experiments ; also the tensile strength and limit of elasticity 
of specimens taken from different parts of the lintel wore deter- 
mined. 

The iron used was of two qualities, marked P and xS respec- 
tively ; that marked P was composed of what was called at the 
foundry of L. M. Ham & Co., where the casting was done, No. 1 
and No. 2 pig. 



30 - TESTS OF THE STEENGTH OF CAST IRON. 

No. 1 pig was prepared by mixing the following ores : ' 

Nesliannock from Pennsylvania 25% 

Franklin from New York 27.5% 

Crozen from Virginia S7 .5% 

No. 2 pig was made by mixing Franklin and Crozen in equal 
parts. 

The chemical composition of P is as follows: 

Graphite 3.00 

Combined carbon. 0.56 

Sulphur . 53 

Silicon 1 . 34 

Phosphorus 1.13 

Manganese 0.33 

Iron by difference 93 . 11 

The iron marked ^S^was made of old scrap. Its chemical compos- 
ition was as follows : 

Graphite 2 . 39 

Combined carbon . 85 

Sulphur 0.07 

Silicon 1 .49 

Phosphorus 1.12 

Manganese . 40 

Iron by difference 93.68 

The specimens for tension were 24 inches long, and about one 
inch square in section. 

The transverse tests were made on window lintels of the follow- 
ing dimensions : 

Inches. 

Length 54 

Breadth of flange 8 

Height of web at the centre of lintel above flange, . . , 4 

Height of web at edge of lintel above flange , 2.5 

Thickness of web and flange 0. 75 

The tensile specimens were cast at the same time, and from the 
same run as the lintels. 

Besides this, one of each kind of window lintels was cut up into 
tensile specimens, and the specimens were so marked as to show 
from what part of the lintel they were cut. 

The tables of tests will now be given, and the following explana- 
tion of the symbolism employed. 

P and S are used, as already stated, to denote the quality of the 
iron. 



TESTS OF THE STJRENGTH OF CAST IRON. 



31 



A and B are used to denote respectively that tlie specimen was 
unplaned or planed. 

1, 2, 3, etc., denote the number of the test made on that particu- 
lar kind and condition. 

L, II., III., denote that the piece has been taken from a lintel, 
and also from what part, as will easily be seen by the accompany- 
ing sketch (Fig. 31.) 



Ill 




Thus P. B, 3 would signify that the specimen was of quality P, 
had been planed, and was the third test of this class. • 

On the other hand, P. B. 3 II., would signify in addition that it 
had been taken from a lintel, and was a piece of one of the strips 
marked II. in the sketch. 



32 



TESTS OF THE STRENGTH OF CAST IRON. 



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TESTS OF THE STRENGTH OF OAST IRON. 



35 



Designation 
of Specimen. 


Area sq. in. 


Breaking 
weight. 


Breaking wt. 
per sq. m. 


Remarks. 










Broke at a flaw at 10,170 lbs. 
■{ re-testfd and broke at a flaw 
at 12,240 lbs. 


P. B. 2. III. 


0.96 


12,240 


12,754 










P. B. 8. IV. 


1.2276 


24,080 


19,616 


Broke at a slight flaw. 


P. B. 9. I. 


0.9513 


20,050 


21,706 




S. B. 5. 11. 


0.8001 


18,890 


23,610 




P. B. 10. I. 


0.9333 


20,050 


21,483 




P. B. 11. II. 


0.741 


16,410 


22,146 




S. B. 6. I. 


8512 


24,790 


29,124 




P. B. 12. II. 


0.725 


14,900 


20,552 




S. B. 7. I. 


0.8385 


23,590 


28,372 




S. B. 8. I. 


0.8645 


21,980 


25,425 




P. B. 13. III. 


0.8624 


13,920 


16,141 




S. B. 9. III. 


1.1063 


30,550 


27,523 




S. B. 10. III. 


1.3275 


24,340 


18,301 





The following is a summary of the breaking weights of the 
specimens not cut from the lintels. 

P.A.I 23.757 

P. A. 2 21,423 

P. A. 3 ..18.398 

P. A. 4 21,409 



4)84,987 
21,247 



P. B. 1. 
P. B. 3. 



21,756 

25,207 



2)46,963 
23,482 



S. A. 1 

S. A.2 

S. A. 3 


24,204 

25,258 

24,706 




3)74,108 


S. B. 1 


24,723 
29,574 


S. B. 2 


23,201 




2)52,775 



26,388 



The conclusions which Messrs. Burgess and Yiele draw from these 
tests are the following, viz. : 

l"". The tensile strength of the iron marked S was higher than 
that of the iron marked P. 

2°. The elongations for a certain load were greater for equal areas 
with the grade P than with the grade S, 

3°. Hence S was a stronger, but, at the same time, a more brittle 
iron. 

4°. With the same grade of iron, the elongations were greater 
in planed than in unplaned specimens. 

5°. The unplaned specimens in these tests had a less tensile 
strength per square inch than the planed. They attribute this fact 
to some slight irregularities in the castings, which were removed 
by planing. 

6°. In regard to the tensile specimens cut from the lintels, it will 



36 TESTS OF THE STRENGTH OF CAST IRON. 

be seen that specimens marked I. and II. broke at higher loads than 
those marked TV., and that the weakest of all were those marked 
III. 

TESTS OF THE TRANSVERSE STRENGTH OF WINDOW LINTELS. 

All the window lintels tested were of the form shown in the 
cut (Fig. 31), and all were snpported at the ends and loaded in 
the middle, the span in every case being 52". From the cut it 
will be seen that the web varied in height, being 4 inches high 
above the flange in the centre, and decreasing to 2.5 inches at the 
ends over the supports. Inasmuch as the section, and hence the 
moment of inertia of the section varied, it became necessary to de- 
duce a special approximate formula suitable to determine the 
modulus of elasticity from the observed deflections. 

In order to deduce this special formula, the moments of inertia 
w^ere first determined at the follow^ing five sections, viz. : 



Distance of section from 
support, inches. 


Moment of inertia of section 
about neutral axis. 


26 

19i 

13 

H 



15.5625 ^. 
12.2072 

9.8600 

6.9773 

5.0300 



These five values satisfy very nearly the equation : 
^ 1.8725 .6.7875 , . ^^ 

Hence this was used for /in the general deflection equation 

d^v M 



and hence was deduced : 



E 



d^ ~ EI 

321.695 W 



where W = load applied, and v = resulting deflection. 

A perusal of the results will show that the jP's which in tension 
bore the least were in everj^ case the ones which in the form of 
lintels stood the most. On the whole, the tensile and the com- 
pressive moduli of rupture compare very well with the tensile and 
the compressive strength of the iron respectively. 



TESTS OF THE STRENGTH OF CAST IRON. 



37 






S. 4. 


S-pan 52". 


P. 2. 


Span 52". 


P. 3. 


Span f2". 




Weight of linle], 118 lbs. 1 


Weightof lihtel, 1201b9. 


Weight of lintel, 119 lbs. 




Deflect, 


E. 


Deflect. 


E. 


Deflect. 


E. 


^3 


Inches, 


Inches. 


Inches. 


500 


0.0000 




O.OOOu 




0.0000 




1,500 






0.0149 


21,590,272 






2,500 


0,0287 


22,456,900 


0.0307 


20,975,359 


0.0347 


18,541,496 


3,500 






0.0477 


20,291,319 






4.500 


0.0588 


21,898,268 


0.0059 


19,637,378 


0.0724 


17,815,104 


5,500 






0.0846 


19,355.172 






6,500 


0,0899 


21,712,057 


0.1022 


19,167,035 


0.1150 


16,952,791 


7.500 






0.1204 


18,953.963 






8.500 


0,1310 


21,447,685 


0.1403 


18,610,508 


0.1572 


16,521,625 


9.500 






0.1601 


18,343.378 






10,500 


0.1544 


21,016,559 


0.1807 


18,070,663 


0.2024 


16,067,818 


11.500 






0.2016 


17.827,158 






12,500 


0,1864 


20,844,894 


0.2251 


17.4.^4,756 i 


0.2522 


15,540,516 


13,500 






0.2492 


17,166,571 






14.500 


0.2202 


20,602,958 


0.27:50 


16,905.859 1 


3092 


14,932,924 


15,500 






0.2989 


16,605,250 i 






16,500 


0.2637 


19,876,418 




! 


0,3756 


14,277,531 




Break ir 


gloftd. 25,120 


j Breakii 


g load. 30,520 ' 


Break'g 


load. 27,200 




Tensile 


modu- 


j 'i'enaile 


modu- 1 


Tensile 


mod- 


* 


lus 


f rap 


1 lus 


f rup. i 


lus oi 


lup- 




ture 


24,592 


ture. . 


29,879 


ture, . 


26,659 

mod- 




Compr. 


modu- 


Compr. 


modu- 


Compr. 




lus ( 


3f rup- 


1 lus 


f rnp- 


uluso 


frup- 




ture. 


75 285 


ture.. 

1 


91,467 


ture 


A1 ROft 









38 



TESTS OF THE STRENGTH OF CAST IRON. 



SUMMARY OF THE EXPERIMENTS OF MESSRS. EASTMAN AND GERRISH. 

The object of this thesis was to determine the constants suitable 
to use in the formulae for detei'mining the strength of the arms 
of cast iron puUe^^s ; and also, incidentally^, to determine the holding 
power of keys and set screws. 

Some old pulleys which had been in use at the shops were em- 
ployed for these tests. They were all about fifteen inches in diam- 
eter, and were bored for a shaft 1y\ inches in diameter. 

Inasmuch as this size of shaft would not bear the strain neces- 




sary to break the arms, the hubs were bored out to a diameter of 
1^1 inches diameter, and key-seated for a key one-half an inch square. 

In order to strengthen the hubs sufficiently, two w^rought iron 
rings were shrunk on them, so as to make it a test of the arms and 
not of the hub. 

The machine used for applying the stress is shown in the cut 
(Fig. 32). ^ . . . ' . 

The pulley under test is kej^ed to a shaft which, in its turn, is 
keyed to a pair of castings supported by two wrought iron /beams, 
resting upon a pair of jackscrews, by means of which the strain is 



TESTS OF THE STRENGTH OF CAST IRON. 39 

applied. A wire rope is wound around tlie rim of the pulley, and 
leaves it in a tangential direction vertically. This rope is connected 
with the weighing lever of the machine, and weighs the load ap})lied. 

The idea of the arrangement was to get a pull upon the rim of 
the pulley as nearly as possible like the belt pnll,to which it is sub- 
jected in practice, and, at the same time to have some means of 
weighing this pull. In practice there are two pulls upon the rim, 
that of the tight side, and that of the loose side of the belt, the 
sum of the two tending to produce a bending of the shaft and a 
compression of the rim and arms of the pulle}^ while the differ- 
ence of the two causes a rotation of the pulley and a bending 
moment in all the arms. It will be seen in the arrangement used 
that while there is no tight side and loose side of a belt, yet there is 
a compression of both rim and arms, which mu-st be very similar 
to that caused by a belt, and a bending moment in the arms such 
as occurs in practice. 

In all the experiments one arm gave way first, and then the 
unsupported part of the rim broke. 

The breaking load of the separate pulleys was, of course, deter- 
mined, and then it was sought to compute from this the modulus 
of rupture of the cast iron, if so it can be called. 

The method commonly given for computing the strength of 
pulley arms is to consider them in one of two ways, viz., either as 
beams fixed in direction at one end and loaded at the other, or else 
to consider tliem as fixed in direction at both ends, thus making of 
each arm a pair of cantilevers, half as long as the arm, fixed at one 
end and loaded at the other. 

If we let 

1 = moment of inertia of section, 

n = number of arms, 

y — half depth of each arm = distance from neutral axis to out- 
side fibre, 

X — length of each arm in a radial direction, 

P — breaking load determined by experiment: 

Then we should have, for the outside fibre stress at fracture, 

.P^ (1) 

^ ~ nl 

if we adopt the first assumption ; or, 

. ^^y (2) 

if we adopt the second assumption. 



40 



TESTS OF THE STRENGTH OF CAST IRON. 





1 






s 




a a 2 - 


g 














• S .pH — < '=*H 










'h 




s- C +- (rf 


o 










-5 






1 










S 

J 
^ 




1 1 1 11 

1 i ^ ro 

2 fi :> -^ g 


03 










o 




C 02 










§ 




^^ 










oo" 




^^ <^^ ^ Jg 


^^ 




1 






o 




- - .S 2^ 

1 1 s©;^^« 

OS es ^ -a "2 .S 


© &D 




C3 






(U 




g <» p Oj w ^ 






it 




c 






H 










>> 

HP 

© 




g g HI'S 

^ 3 p -S^ CI. 
















g^ g' =« O CS 3 






5^ 






H^ h^l O rH 


II 




o 






-S 


0) 


^ 1§ ^g) 








o 


o 




o 


© •- 






V 


i; 


f-l 


0) 


«:; 


© 05 S: fc- 






c 


rO 


rO 


-^ J2 


^ 


^ -^ -5 = !/ 






li 


Ti -d 22 ^' 


H 


• S 3 




* 




s| 


Oi (U S c 


^^ 


S = 


^ .-^ . ^^^ 








U o eS 


5'^ 

-si 




*3^ ^'^ -rO S P^ 

-^ o o ^— ^^^ 




1^ 


C5 


J> 


O 


<?^ 


O lO o 




■H< 


1—1 


lO 


CO 


CO 


CO TH cc 




CO 


CO 


?o 


o 


1—1 


iO 1> lO 




CO 


II 
















"M 


tH 


CD 


Oi 


t-h" o" ^ 




co" 


"^ 


■^ 


'^ 




T— 1 


t— t T- TH 




T^ 

^ 


11^ 


to 


'^ 


o 


lO 


o o o 




CO 




«5 


^ 


CO CO CO 






'^^ 


CO 


■1-1 


CO 


O "*' o 




lO 


11 
















CO 


CO 


oi 


od~ 


co" tT CO 




CO 


^ 


(M 


CO 


CO 


^? C5 CO 




C5 




o o o 


o 


"~o~" 


(^ 


CS o o 







Breaking weight. 


ggg 


o 
1— 1 


^ 


^ 


^ o ^ 
























iO lO CO 


CQ 


«o" 


■^ 


'^ CO -^ 






w 




^!-Nec(-c -x> 


itO 




if.i» 


r-i^ nH'icloofiilN H^Ni-l** 






g 


x> 


c^«^^H^ 


H„ 


<^-i!S 




c»|r> <si« c^lr^cHirs 






es d 


^ 


XXX 


X 


X 


X 


X X X X XX 






•Si 


"eS 


Hoc^fN 




«1« 


— :■* 










i-l^« 


CCJ 


tH 


tH 


.,_( .^ -r-l y-> tH T-l 






B 


-^:i:H- 


'-'IS 


hn 


«:s 








g« 


XXX 


X 


X 


X 


X X X X X ^ 






a 1 
S 


Hx«<» 




«p 




'rf': Hx-LfH- ^.,.„ 






i-H r^ (M 


CO 


1—1 


1— 1 


tH ^ tHtH tH t-I 






Number of arms. 


I lOlO «o 


o 


o 


50 


to iOiOlO iOiO 






Length of arms. 


I "^^4^ 




^ 


lO 








Thickness of hub. 


1 c.«e:c,. 


Rr* 




:!s 


^- 1—1 








( ^]^.t^^f 


, .J, 


w!» 


«■* 


-<i-*— '-t-i'-t — '-*■ 






Width of hub. 


1 ^^=^ 


CO 


CO 


CO 


-«*< COTt*^ '«*<'* 






Thickness of rim. 


1 -''^;S<e 


"Jf 


">■* 


< 


-^^ >tA^<if^'^ ^-^^ 






Face. 


1 S5'< 


«e 






•^^ h:s ;? H- 




a5 




1 '^ 'CO 


CO 


CO 




CO COTf< co-^ 




_Sc 




1 HX 


r^N 




4^ 


-•lit) «(-t 




a 


Diam. of pulley. 
Number of test. 


1 T-f »-H tH 

1 rlCOOO 






»0 T*<T*< CO iO05 
TH 0!{^1-l TH-rH 




t- 
© 


lO 


to 


t> 00 OiO T- CQ 

T— 1 TH TH 




<i1 



TESTS OF THE STRENGTH OF CAST IRON. 41 

These formulae are both based upon the assumption of arms of 
uniform section, either straight or else symmetrical with respect to 
hub and rim. 

Other formul?e might be deduced which assnme a variable sec- 
tion, but it would not seem to be worth while, in view of the fact 
that the bending moment is probably unequally diyided among the 
arms. Hence the students confined themselves to computing the 
values of y from each of the above formulae, thus obtaining average 
values of the constants to be used in these formulae for the purpose 
of determining approximately the sti'ength of the pulleys. (See 
table of the results on previous page.) 

Conclusions from these Tests. 

1st. A low value of the modulus of rupture of cast iron should 
be used in the ordinary formulae for designing pulley arms, due to 
the fact that a load at the rim acts more upon some arms than upon 
others, as shown by the fact that, in four out of eight of the tests, 
one arm broke first, and this one always occupied the same position. 

2d In every case but one, of these four, a greater load than the 
original was afterwards put upon the pulley, and no other arm 
broke, but the rim gave way by crushing. In this one case 
excepted, the arms afterwards stood a greater load proportional to 
their number before breaking. 

3d. In the tests on the single arms to be described next, the mod- 
ulus of rupture rose as high as 55,000 lbs. in some cases, and in no 
case went below 35,000 lbs. 

Tests of the Separate Arms. 

In the cases of numbers, 5, 7, 8, 9 and 10, some of the arms were 
not broken, the rims were now broken off, and the remaining arms 
were tested separately, the pu^l being exerted by a yoke hung over 
the end of the arm, the lower end being attached to the link of the 
machine. 

The arms were always placed so that the direction of the pull 
was tangent to the curve of the rim at the end of the arm. 
The actual outside fibre stress at fracture was then determined by 
calculation from the experimental results, and is recorded in the 
following table : 



42 



TESTS OF THE STEENGTH OF CAST IRON. 





Dimensions of section 


Bend of arm with or 
against load. 


Actual outside 


Average modulus 


Number of 
Arm. 


at fracture: all ellip- 
tical. 


fibre stress at frac- 
ture. 


of rupture for eachr 
pulley. 


5-1 


1-1% X il 


against 


44,396 


44,396 


7-1 


U X I 


against 


3(),802 




7-2 


m X i 


against 


39,537 




7-3 


m X i 


with 


46.407 


40,915 


8-1 


m X n 


against 


35,503 




8-2 


m X u 


against 


36,091 




8-3 


1:H X ]^ 


with 


39,939 




8-4 


m X -H 


with 


42,469 


38,500 


9- 1 


1A X f 


against " 


41,899 




9-2 


l-h X u 


againscj 


44,148 




9-3 


I'h X f 


wit n 


55,442 


47,163 


10-1 


li X u 


against 


54,743 


1 , 


10-2 


1-^ X -15. 


against 


50,943 




10-3 


lit X -,^- 


[against 


38,6u5 




10-4 


1^ X -^i 


with 


55,229 ■ 


49,880 



Total 642,153 

Average 42,810 

In order to show how the results in the preceding table were 
deduced from tlie experiments, the calculation will now be given 
in full for the first, or 5-1 (Fig. 33). 




^ The force W, which is equal to the load upon the arm, is 
resolved into two components, OB and B IF. Both these compo- 



TESTS OF THE STRENGTH OF CAST IRON. 43 

nents act on the arm at the point 0^ OB in the direction OB^ and 
^ITin tlie direction OA, 

The first OB acts as a pull at the end of a cantilever of length 
6^(7, and is calculated accordingly; the second 7? TT acts as a pnll 
in the direction OA^ and produces stresses similar to those acting 
in a hook, where the distance fi'om the line of pnll to the centi'e 
line of the hook tension is CM, 

The formula used for the cantilever is/i = -~^ where J!f equals 

the pull times the length of the arm, y equals half the depth and 
/equals the moment of inertia of the section. 

The formula used to determine the greatest tension due to the 
force B IF is 

_P Pny 

where P equals the pull, A equals the area of the section =— — , n 

equals the distance CM^ and y equals the half depth. 

The sum ofy^ and/" gives us the greatest fiber stress at fracture, 
or the modulus of rupture of the iron of the arm. The breaking 
load of this arm was 1645 lbs. Hence : 
OW=\U^. 

0B= W cos 23^° = 1508. 
JBW= 6> TF 5^?^ 23J« = 655. 

. . ^ (1508) (2 25) (32) _ 
"'^^ TT (0.5312) (1.5625/ ~ 
Also, 

.^ (655) (4 ) (655) (3.487) (32) _ 

•^' 7t (0.5312) (1.562) ^ 7t (0 5312) (1.562)^^ 

Hence ^/l 4-/2 = 44396, as recorded in the table. 

The other values are similarly calculated. 

An inspection of the table will show that the modulus of rupture 
figures out higher when the bend of the arm is with the load than 
when it is against it, and the value will be found to be very much 
higher than the values of/ derived for the pulleys with the rims on. 



44 



TESTS OF THE STKENGTH OF CAST IRON. 



Tests of the Holding Power of Set Screws. 

These tests were all made hy using pulley Iso. 12, the pulley 
being fastened to the shaft by two set screws and the shaft keyed 
to the holders; then the load required at the rim of the pulley to 
cause it to slip was determined, and this being multiplied by 



|-|x 2 



^.037, 



gives the holding power of the set screws. 

The number 6.037 is obtained by adding to the radius of the 
pnlley one-half the diameter of the wire rope, and dividing the 
sum by twice the radius of the shaft, since there were two set 
screws in action at a time. The set screws used were of wrought 
iron, I of an inch in diameter, and having ten threads to the inch ; 
the shaft used was of steel and rather hard, the set screws making 
bat little impression upon it. The set screws were set up with a 
force of 75 lbs. at the end of a ten-inch monkey wrench. The set 
screws used were of four kinds, marked respectively A, B, (7, and 
D. They n)ay be described as follows: 

A, ends perfectly flat, ^" diameter. 

B, radius of rounded ends, about J inch. 

C, radius of rounded ends, about ^ inch. 
B, ends cup shaped and case hardened. 
The results are ffiven in the followino^ table : 



No. of test. 


A 


B 


c 


J) 


1 


1,413 


2,747 


1,902 


2.807 


2 


2,208 


2,747 


2,354 


1.9C)2 


3 


2,131 


3,079 


8,079 


2.173 


4 


2,143 


2,958 


2,958 


2.203 


5 


2,294 


2,897 




2,958 


6 


2,203 


3,048 




2,717 


Av. 


2,064 


2,912 


2,573 


2,470 



The following remarks should be made in regard to each kind 
of tests. 

A. The set screws were not entirely normal to the shaft ; hence 
they bore less in the earlier trials before they had become flattened 
by wear. 

B. The ends of these set screws, after the first two trials, were 



TESTS OF THE STKENGTH OF CAST IRON. 



45 



found to be flattened, the flattened area having a diameter of about 
J of an inch. 

C. The ends were found, after the flrst two trials, to be flattened 
as in B. 

D. The first test lield well because the edges were sharp, then 
the holding power fell off till they had become flattened in a man- 
ner similar to B^ when the holding power increased again. 



KEYS. 



The experiments on keys were made with pulley ]N"o. 11. n 
all cases where the keys were not as wide as the key way they were 
wedged in with hardened steel pieces, the hardened steel piece in 
the pulley hub being as long as the hub was wide. 

The load was applied as in the other tests, the shaft being firmly 
keyed to the holders. The load required at the rim of the pulley 
to shear the keys was determined, and this multiplied by a suitable 
constant, determined in a similar way to that used in the case of set 
screws, gives us the shearing strength per square inch of the keys. 

The keys tested were of eight kinds, denoted, respectively, by 
the letters, A^ B, C, 2>, E^ F, G and H^ and they may be described 
as follows : 

A^ were of Norway iron, 2" x J" x ^' \ constant = 18.5184. 

B, were of refined iron, 2" x ^' x ||-''; constant = 18.5184. 

(7, were of cast or tool steel, 1" x J" x i|" ; constant — 49.78. 

2>, were of machinery steel, 2" x J" x ^"; constant = 18.5184. 

E, were of Norway iron, If x |" x y\" ; constant = 18.5184. 

F^ were of cast iron, 2 x J^ x J|; constant — 18.5184. 

G^ were of cast iron,^l^ x I x t\ j constant = 18.5184. 

H^ were of cast iron, 1 x | x ^\ ; constant = 18.5184. 

The shearing stresses per square inch, as determined from the 
experiments, are given in the following table : 





A 


B 


c 


B 


E 


F 


G 


II 


1 

2 
3 
4 


41,202 
41,758 
40,184 
47,760 


36,482 
37,334 
39,254 
39,166 


100,056 
91,344 


70,186 
66,110 
64.630 
66; 574 


37,036 
37.222 
36,850 


34,166 
36,944 
30.278 
30,758 


38,700 
37,222 


29,814 

38,978 


Av. 


' 42,726 


38,059 




66,875 


37,036 


33,034 







46 TESTS OF THE STllENGTH OF CAST IRON. 

REMARKS. 

A, Some crushing took place before shearing. 

B, Sh'ght crushing took place before shearing. 

O. In the second test one of the wedges slipped and did not bear 
on the whole length of the key. 

K Inasmuch as these keys were only Jg" deep, they tipped 
slightly in the key way. 

H. In the first test there was a defect in the keyway of the 
pulley. 



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L3 



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